Grease gun



' Sept. 8, 1925.

G. M. HARTSOCK GREASE GUN Filed July 15, 1921 Patented Slept. .8, 11925.

UNITED Paisiw -oFFlci-z.

GUY MYERS mirrsocmor Damon, meinem, AssIeNoa To sTUnEBaxEa conj roaaron, aconoaa'rron or NEW JERSEY. Y

'GEEASE our.

Appuauon'mea July 1s, 1921. 'serial Eo. 4,841,987.

' To all whom it may concern:

' Be it knownthat I, GUY MYERS HART- sooK, a citizen of the United States of America, and resident of Detroit, in the county of Wayne and State of Michigan,

have invented certain new and useful Imy provements in Grease Guns, of which the following is a specification. y

My invention relates to improvements in Y devices for introducing grease into cavities provided to accommodate the same, by

means ofpressure. 'A

` Heretoforeit has been the practice to introduce the grease into these cavities Vby means of manually operated devices, such as a grease gun having a piston moved by a manually operated screw or like device.

A These devices when designed to' give sui,

. cient pressure were correspondingly slow in operation and the pressure was not evenly applied as it W'ould vary inversely with the v speed at which the plunger was operated; that is, the'higher the pressure the slower the operation, and vice versa.

My invention minimizes this difficulty, if it doe's'not entirely eliminate hit, because the necessary pressure is obtained byia device operating on the principle of differential pistons, the larger piston being operated by fluid pressure, either thru the medium of. a

gaseous substance'such .as air or vof a liquid such as water, the smaller piston acting on the grease to be delivered into the cavities,

and forcing it into the same. By this arrangement it can'readily be seen that by varyin Ythe pressure of the liuidy on the t larger piston, or by varying the ratios of the areas of the two pistons, or by varying both,

. any desiredl pressure can be obtained to 40 force the grease into the cavities. I

' The overcoming of the relative slowness of operation, is /perhaps a natural outcome of using a'device operating on the rinciple 7 of diierential pistons, or at least t l 's prin- *ciple with its inherent construction offers a natural expedient in the solution of speed- -ingup the operation of delivering the grease. Specically, the speeding up of the delivery of grease depends upon the number of reciprocations 0f the piston acting on the grease in a given length of time. In this particular device passages lead from either side of the large piston to a two-way cock, controlling the admission of 515V `iiuid pressure to either side of the piston and therelieving of the pressure from the oppoi site side. This operation, the admission of' vpressure to one side of the piston and the lrel1ev1ng of pressure from the other side, is

controlled by turni-ng a twoway cock, an operation which under practical considerations takes no appreciable time. The action of the pistons, once`pressure has been applied is much faster than any manually 0p-` erated device and therefore the delivery of grease, is much greater inqcomparison.y y. I,

'Having described the advantages of this invention, a more detailed description vwill A follow, reference' being had to the accom-v panying drawing which is a longitudinal section ofva device embodying my present mventlon. l

The main casing 1 is formed to provide a relatively large cylinder 2 in one end thereof and an axiallyextending sleeve 32 having a central `opening communicating with the cylinder 2. A cap y33 forming a head for the open end f the cylinder 2 is secured thereto by bolts orother suitable means to form a unitary'part thereof and has an axially extending sleeve 34corresponding with the sleeve 32 butoppositely disposed-in rela,

tion thereto. A piston `5 axially slidable in the sleeves 32 and 34 has threads lformed thereonv adjacent its mid-portion and re` ceives'thereon the main piston?) which engages the cylinder 2 and is reciprocable therein. The sleeve 32 is interiorly threaded and receives therein the gland member 10 which is provided with a bore or cylinder 4 to slidably receive the right hand end of the' piston 5 and has extending therefrom a hollow, corrugated nipple portion 35 which has an opening or assa 36 communicatin with the bore di' cylginder 4.- A suitabl pacln'ng 3 1 is provided at theinner end .of

'the gland member 10 to seal the joint'between the glandmember 10 and vthe sleeve 32 and the sleeve 32 and piston 5. A suitable lock nut 26 sScreW-threaded on 100 the gland member 10 to prevent the inadvertent turnlng or loosening of the same relative to the sleeve32.

`The sleeve 34 whichv is illustrated as integral with and extending from the cap 33 is 105 also internally threaded and receives therein the gland member- 11 which issimilar to the gland member 10 and like the latter is provided vwith'a bore or cylinder 37 which 4receives the left hand end 'of the piston 5 110 for a purpose to be described later. A lock nut 26 is also screw-threaded on the gland member 11 to prevent rotation of the same relative to the casing 34. The gland member 11 is also .provided with an extending nipple 38 exteriorly threaded to-receive a flexible hose coupling (not shown) or for making a suitable connection with a member to be lubricated. The nipple 38 is provided with an axial opening 39, the outer end of which is of a larger diameter than the inner end which communicates with the cylinder opening 37. A suitable packing 31 is provided at the inner end of the gland member 11 for the same purpose as the packing 31 in the gland member 10.

Thelpiston 5 is provided with an axial opening 19 which extends therethrough from end to end communicating with the cylinders 4 and 37.` A ball 20 is positioned in the passage 19 adjacent its outlet or left hand end and is normally seated against a tapered flange forming a reduced portion thereof by a spring 27 which seats at its one end on the ball 20 and at its opposite end on the pin 27 secured in the piston 5 adjacent the mouth of the opening 19. The ball 2O forms a check valve which allows passage of grease thereby in one direction only, that is, from the cylinder 4 to the cylinder 37, but not vice versa.

To insure the passage of grease or other substances through the passage 19 into the cylinder 37 upon Yright hand movement of the pistons 3 and 5 and to prevent the grease from being forced back through the passage 36, a valvular means is provided in the passage 39 which will seal the passage and cause a vacuum in the cylinder 37 upon movement of the piston 5 to the right so that the grease in the cylinder 4 will be sucked through the passage 19 past the ball 20 and into the cylinder 37. The valvular means comprises apiston 12 reciprocable in the reduced portion 13 of the opening 39. This piston is provided with a longitudinal passage 17 extending from the rear or'right hand face to a transverse passage 18 provided near the forward or left hand end thereof. A pin 15 forming a stop to limit the movement of the piston 12 is positioned in the reduced portion 13 of the passage 39 adjacent the cylinder 37 and a pin 14 positioned in the large portion of the passage 39 limits the movement of the piston 12 in its outward movement. A-spring 16 interposed between the stop 14 and the piston 12 tends to push the piston 12 toward the stop 15 and the passage of grease past the piston 12 is normally prevented dueto the fact that the walls of the reduced portion of the passage 39 cover or close the transverse opening 18 to the passage of the grease. Thus on the rearward or right hand movement of the pistons 3 and 5 a suction will be created in the cylinder 37 which will cause the piston 12, assisted by the action of the spring 16, to follow the piston 5 until it abuts against the stop 15 and on the forward or left hand movement of the pistons 3 and 5 thevpiston 12 will be moved forward against the action of the spring 16. lVhen the piston 5 is moved forwardly or to the left pushing grease before it, the grease is put under pressure which is transmitted to the piston 12 and when sufficient pressure is exerted thereon to overcome the action of the spring 16, the piston 12 will move forwardly to bring the transverse opening 18 therein past the end of the reduced portion of the passage 39, at which time the grease is free to flow through the passages 17, 18 and 39 to the grease cup or part to be lubricated.

The discharge ends of grease guns are usually connected to the grease cup or part to be lubricated by a fiexible tube or other suitable means. As a considerable pressure is built up in the tube or connecting means, when grease is inserted therethrough, a certain amount of the grease will be extruded from the tube upon disconnecting the parts due either to the pressure, or, the tube having been previously expanded, to the corresponding contraction of the tube upon relieving the pressure therein. It will be apparent that if an ordinary check valve was substituted for the piston 12, it would be impossible to relieve such a pressure in the discharge connections because the check valve would seat immediately upon backward movement of the pistons 3 and 5. To relieve the pressure in the connections, the piston 12 is provided, which moves a limited distance with the piston 5 and thereby relieves the pressure above described. When the gun is discharging grease, the piston 12 will move forwardly to expose the trans-- verse passage 18 therein to the enlarged portion of the passage 39 and will assume that position at the end of its discharge stroke, whether it be the full stroke of the piston 3 or only a part thereof and will assume that position when a quantity of grease has been received in the cylinder 37 and then pressure applied to force the same into the passage 39 to move the piston 12 forwardly against the compression spring 16. Upon backward movement of the pistons 3 and 5, a suction is created in the cylinder 37 which tends to draw or move the piston 12 with the piston 5 against the stop 15 which al# lows for expansion of the grease in the connecting tube and thereby relieves the pressure in the discharge connections so that upon disconnecting the same no grease will be exuded therefrom.

In orderthat no grease which may escape past the outside surface of the piston 5 and under the packing 31 or 31 may be carried into the main cylinder 2 and thereby oblUl) vnon-rotatably secured to provide a means` for rotating the valve 40. A gland 29 ,sur-A rounding the stem 7 is screw-threaded into the casing 6 and a packing 30 is preferablyl inserted between the inner end of the gland 29 and the valve 40 to revent leakage of\ air or liquid past the valve and between. the gland 29 and valve stem 7. The valve 40 is providedr with two separate passages 'positioned perpendicular to the axis of the valve and in different planes, each of which comprises an opening 41 and a second opening 42 communicating therewith and radially disposed in relation thereto. The passages are identical with the exception that the lower openings are turned 90 about the axis of the valve 40 with respect to the upper openings. ,A vertically disposed blmd passage 24 plugged at its open end is formed in the casing 6 and communicates with the passages formed in the valve 40 by cross passages 25 and 43 when the valve turned to bring its passages in mating relation therewith. A corrugated nipple 9 is screwthreaded into the casing 6 and is adapted to be connected with an air hose or other suit` able device (not shown) wherebyxair under pressure can be delivered to the passage 24 through the laxial passage 44 formed inthe nipple l9. A horizontal passage 23 formed in the casings 1 and 6 extends from the valve 40 in the plane of the upper openings 41 and 42 to the cap 33 where it' joins the passage 22 formed in the cap 33 whichvmmunicates with the cylinder 2 on .the left hand side of the piston 3. A Ue v inthe casings 41 and 6 extends from the valve 40 in the plane of the lower openings 41 and 42 in said valve to the cylinder 2 on the right hand side-of the piston 3.

.Each radial opening 42 communicates with the respective passages 23 and 45 when.

' brought in matchingrelation thereto and the openings 41 connectingwiththe' passages 42 communicate with a passage, (not shown) leading to the atmosphere. As shown in the drawing, the valve 40 is posi-- tioned so that the lower passage-41 is in communication with the passages 25 and 45 vand air under pressure is admitted to the zylinder 2 through the passa 44, 24, 25 41v and 45 on the right hand sid of the pis ton 3 to move the same to the left. At the same time the upper passage 42 in the valve /40 is in communication with the passage 23 and the opening 41 connecting with the up- Y per passage 42 is in direct communication with the atmosphere, thereby relieving an pressure at the left of the piston 3 in the cy inder 2 when the piston 3 is moved in that direction. It will be apparent that when the valve 40 is turned to bring the upper passage 41 into communication with the passages `43 and 23, air under pressure will be admitted-therethrough and that the piston 3 will move from the left to right, at i which time the port 41 connecting with the lower passage 42 will be in direct communi-` cation with the atmosphere to relieve pressure on that side of the piston 3. Thus, by

turninglthe handle 8 which controls the y valve 40, the pistons 3 and 5 will be moved to reciprocate when a suitable source of air or other liquid pressure is applied to the passage 44. 'It will also be apparent that if the nipple 35 is connected to a source of grease or other substances which it-is desired to pump' and when the pistons 3 and 5 move from .the extreme right'hand position tofthe extreme left hand position as shown in the drawing, the ball 20` will seat and a vacuum'will be produced inthe cylinder. 4 which will cause the grease'to he drawn into vthe cylinder 4 back ofthe piston 5.

Upon reverse movement ofthe pistons and 5, the ball 20 will be raised from its seat and the grease will flow `from the passage -19 to the cylinder `37 from whence it will be forced through the passage '39 to the part to ybe lubricated upon the next leftl hand movement of the pistons 3 and 5.

`Having described the detailed parts of the drawing and explained the construction of the device, it -is thought that the operation of the same will be readily understood. The nipple 35 is preferably connected by a flexiblel tube to asource of grease supply, the'nipple e318 is connected with the part to be lubrlcat to a source of fluid pressure such as airV or water, but preferably air.` Assuming that the piston 3 -is at the right hand side of-the' cylinder 2 and the handle 8 turned to bring the lower passage-41 in the valve 40 into and the nipple 9 is connected.

communication with the passages 25 and 45,

it will be seen that'air underpressure' will itothe right hand side ofthe piston the cylinder 2, which will move thefjsame and the piston 5l'to the left.V As

the'ball 20 is normally seatxed against -the inclined wall of the-passage 19 inthe iston 5, avacuum will be created in the cy 'nder 4 when the piston 5 is moving toward the left and grease will be drawn into the cylinder 4. When the pistons 3 and 5 have moved to the/extremeleft hand position as shown in the drawing, the handle 8 is turned to bring the upper passage 41 in the piston lso 4.0 into communication with the passages 43 and 23, at which time air under pressure will be admitted to the cylinder 2 at the left hand side of the piston 3, which will cause the pistons 3 and 5 to move toward the right. As the pistons 3 and 5 move toward the right, grease will be forced through the passage 19 in the piston 5, whereupon the ball 20 will be raised from lits seat and the grease will flow from the passage 19 into the cylinder 37' at the left of the piston 5. Upon the secondleft hand movement of the pistons 3 and 5, the grease in the cylinder 37 will be forced into the passage 39 and pressure exerted against the piston 12 will move the same to the left against the action of the spring 16 until the transverse passage 18 in the piston 12 will be moved to communicate with the enlarged opening in the passage 39, whereupon ,the grease will be forced from the passage 39 into the part to be lubricated. As the pistons 3 and 5 again move to the right, the piston 12 will also move to the right to abut against the stop 15 and a vacuum will be created in the cylinder 37 upon such movement of the pistons and the right hand movement of the piston `12 will at that time relieve the pressure created in the connections between the nipple 38 and the part to be lubricated so that this connection can be broken and another connection ma'de with the part to be lubricated without theinconvenience and annoyance of having grease escape from the connecting member due to the previous pressure built up therein. It will thus be seen that each left hand movement of the pistonsv 3 and 5 draws a quantity of grease into the cylinder 4 andy each right hand movement of these pistons will transfer the major portion of the grease from kvthe cylinder 4 to the cylinder 37 and each subsequent left hand movement of the pistons will force -the grease from the cylinder 37 to the part to be lubricated. t

It will be understood that changes may be made in the specifiedY invention described, such as substitutions of eouivalents, without departing from the spiritvof functions of the invention, the scope of which is commensurate with the appended claims.

Having thus fully described the invention, what I cla-im as new and desire to secure by Letters Patent is:

` 1. A device of the class described comprising a casing having three cylinders, two of whichv being of substantially the same bore and the third being of a large bore; interconnected pistons reciprocable in said cylinders; means for admitting fluid under pressure to either side of said larger piston and simultaneously relieving fluid from the opposite side thereof to reciprocate said piston; means for admitting viscous lupiston;

pressure bricant into one of said smaller cylinders; a longitudinal passageway in said smaller valvular means in said passageway to allow the lubricant to pass therethrough in discharge direction only; an outlet in said casing whereby lubricant is discharged from said device; valvular means in said passageway whereby pressure is automatically relieve-d in said outlet passage; .and means to limit the movement of said last-named valvular means.

2. A device of the class described comprising a casing provided with three cylinders, two of which being of substantially the same bore, and the third being of a larger bore; interconnected pistons reciprocable in said cylinders; means for admitting fluid under pressure to either side of said larger piston and means for simultaneously relieving pressure from the opposite side; a passage way thru said smaller pistons, a check valve therein whereby grease is forced in one direction only therethru; and a discharge outlet connectedwith, the chamber into which the grease is to be introduced. A

3. In a grease gun, alargepiston, smaller projecting axially therefrom in both directions, a casing providing cylinders for said pistons, an axial passageway extending from the face of one of said smaller pistons to the face of the other, means for connecting one of said smaller cylinders with a source of grease supply, means for connecting the other of said smaller cylinders with a xpoint of'deposit, means for automatically relieving pressure in the last`named means upon movement of said pistons in one direction, and meansfforv. admitting a fluid under pressure to either side of said large piston and simultaneously relieving pressure on the other side thereofl to operate said pistois. Y.

4. lgrease gun comprisin a casin rovided with three cylinders, diie of wligiclli is larger than the other two, a sin le piston 'member reciprocable in' said sma ler cylinders, a piston for said large cylinder mounted on said first named piston intermediateV y its ends, a discharge opening-leading from ton and simultaneously relieving fluid pressure from the other side thereof to operate said pistons. Y

Signed by me at Detroit, Michigan, this 13th day of July, 1921.

GUY MYERS HARTSOCK. 

